package 比赛.中兴捧月2022.练习;

import java.util.Scanner;

public class 素数判断 {
    public static void main(String[] args) {
        Scanner in = new Scanner(System.in);
        int n=in.nextInt();
        if(n<2){
            System.out.println("yes");
            return;
        }
        boolean[] data=new boolean[n+1];
        for (int i = 2; i < data.length; i++) {
            int middle=1;
            if (data[i]==true)
                continue;
            while (++middle*i<=n)
                data[middle*i]=true;
            if (data[data.length-1]){
                System.out.println("no");
                return;
            }
        }
        System.out.println("yes");
    }
}
